ELECTRORHEOLOGICAL BEHAVIOR OF SUSPENSIONS BASED ON POLYDIMETHYLSILOXANE FILLED WITH HALLOYSITE

Abstract

The rheological behavior at 20 °С of electrorheological fluids based on silicone oil filled with halloysite nanotubes with different water content was studied. Flow and viscosity curves, storage and loss moduli were measured using a cylinder-cylinder rotary viscometer. The frequency dependences of electrical conductivity and dielectric loss tangent were obtained by dielectric spectroscopy. When an electric field is applied to the samples, their rheological behavior changes - the values of the yield stress increase. In this case, the viscosity curves exhibit an elastic behavior at low shear stresses and exhibit a Newtonian flow when the yield point is overcome. The frequency dependences of the storage and loss moduli confirm the results obtained on the flow curves. The electric field intensity influence on the magnitude of the electrorheological effect was also investigated. The effect of water presence on electrorheological and electrophysical properties was shown. Electrorheological fluid with a small amount of water exhibits a better response to the electric field application, as evidenced by higher values of the yield stresses in comparison with the sample containing drained filler. The small water content does not have a strong effect on the electrical conductivity of the systems under study, but its presence significantly changes the form of the dielectric loss tangent - the contribution of the electrical conductivity to the relaxation processes is significant, and the nature of the relaxation transitions changes due to the different polarizabilities of the wet and dried filler. This work demonstrates the prospects of using nanoscaled fillers with a high aspect ratio as the dispersed phase for electrorheological fluids.Forcitation:Kuznetsov N.M., Belousov S.I., Bessonova N.P., Chvalun S.N. Electrorheological behavior of suspensions based on polydimethylsiloxane filled with halloysite. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 6. P. 41-47